CMS Pixel Barrel Detector Assembly and Insertion

CMS Pixel Barrel DetectorAssembly and Insertion

Hans-Christian Kästli, PSI

Vertex08, 28. 7. 2008

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Contents

• Introduction, system overview

• Detector assembly

• Survey

• Service cylinder

• Transport and insertion

• Commissioning

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CMS Pixel Barrel Detector

CMS Pixel Detector3 barrel layers2x2 disks

Pixel barrel Module

Radius [cm] # Modules # Pixels [106] Area [m2]

4 128 + 32 9.6 0.15

7 224 + 32 16 0.26

11 320 + 32 22.4 0.42

total 672 + 96 48 0.83

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Pixels half barrel

BPix supply tubes

FPix half disks with supply tube

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System overview

PLLCCULVDSmux

mDOH AOH

FEC FED

BARRELENDFLANGE

SERVICETUBE

COUNTINGROOM

ALT

I2C

I2C

L1A(trig, cal, sync, reset)

CLK

CLK

I2C

AnalogOut

SlowI2C

HardReset

CLK L1A Analog out

FEC

DOH

DATA CLK

SlowI2C

Delay

LCDS drivers

Gate-Keeper

electricaloptical

DATA

SlowI2C

SlowI2C

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Detector Integration• ~800 modules to mount

• Can do manually if good tooling designed

• Turned out to be very efficient (up to 60 modules per day) and reliable. Only 3 modules destroyed, O(10) could be repaired (broken wire bonds, bad connector)

Main integration tool

Angle selector

Layer 3 mechanics

Mounted modules

Arm rest

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Module in protection box for safe handling whilecutting+bending cables, soldering plugs

Transfer tool

Pick up with mounting clamp

Module ready for mounting

Put cables through support structure

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Putting module onto mechanics

Put in screws through mounting clamp. Module still fully protected

Remove mounting clamp

Tighten screws

Bring cables in place

Plug in on end flange and test

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Survey

Object very ‚crowded‘

Difficult to survey

No fiducial points foreseen on mechanical structure

Decided to only survey module positions per ladder in 2D. No higher level structures.

•Simple manipulations, no risk for damages

•Fast and easy procedure with reasonable accuracy

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Principle of Survey

+1

zLadder center

End flange

PicturesModules

Take pictures of region where modules are facing each other. Connect modules positions from center outwardFor BPix a ladder is not a mechanically independent objectThere are no fiducial points on a ladder Define ladder through its center of gravity (of all 8 modules) and the direction by fitting a line through the module centers

0-1-2-3 +2 +3

++

+ + + ++

+

Module centers

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Photographic Survey

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Example Picture

Known distance, used to get scale of picture

Alignmnet mark on active material, one at each cornerSize: 100m

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Position Measurement• Use optical pattern recognition software• Interpolation of brightness• Pattern found with subpixel accuracy• Very good resolution for single alignment

marks: = 1.7m/√2 = 1.2 m !

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Misalignment

Shown is position and angle of module w.r.t. ideal position on ladderMeasured misalignments: 50m in u=r-phi (gauss)

70m in v=along beam axis (gauss)2.5 mrad in ( ~ gauss)

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Error propagation

0z

-1-2-3

Ladder centerEnd flange

PicturesModules

• Single pictures are very precise: O(1m) resolution of fiducial points• But: only relative measurement

• Large (z-dependent) lever arm• Errors add up along z• Final error an order of magnitude larger at z=±4

Effect of errors in angle

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Errors

• Plotted is • Error is z-dependent: each peak corresponds to position ±n on the ladder. It

gets bigger further away from the ladder center

Covariance(u,u)

Results: u (=r-phi) v (along beam pipe)

Mean error 9.5m 4.5m 240 mrad

Outermost modules 20m 7m 370 mrad

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Supply tubes• Two ~3m long supply tubes build

independent system unit together with half of the BPix detector.

• Supply tube containes:– Opto hybrids for 1152 optical r/o links

– Optical control links for FE programming

– Optical control link for detector control

– Boards for power distribution

– Temperature and humidity sensors

• Half of BPix detector assembled in a special transport box

• Complete system assembled, debugged and tested at PSI

• Transported as a whole to CERN

• Retest after transport showed no damages

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Detector side:r/o optical driverssector control electronicsKapton cables to detector end flangeTemp / humidity sensors

Off detector side:Last cm2 filled with optical

connectors and fibresPainful slack management

Detector control electronics

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Insertion

• CMS Pixel detector designed for fast insertion – Independent from rest of tracker– Pixel barrel and end disks independent systems– Replacement possible in O(1 week)

• Last subdetector to be installed in CMS

• Installation time: a few hours (first time a bit longer) + check out ~1 day

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Insertion

Transport cassette

Temporary insertion rails

Permanent insertion rails

Carbon fiber tube within Si strip tracker

Beam pipe

Patch pannel to connect services

System supply tube – detector – supply tube fully assembled and connected

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Tests before InstallationClearance test with real detector and mockup rail systemClearance between left/right halfs:1mm!Problem with cable found and solved

Insertion test with ‚commissioning system‘: true mechanical structure, prototype supplytube, only one sector (1/32) equipped with modules

Test transport of ‚commissioning system‘ from PSI to CERN with

accelerometers

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Commissioning ongoing...

• Installation done July 23/24

• All cables and fibres connected

• Cooling is (finaly) working

• Lots of problems encountered (collision during insertion, wrong cabling, bad connections...) and solved thanks to outstanding effort of S. Streuli, R. Horisberger, W. Erdmann, T. Rohe, D. Kotlinski and others ! Still installed in 1.5 days!

• Checkout of -X side sucesfully done over weekend, 100% operational

• +X side under test now

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Checkout Procedure (I)• Phase I (now): Fast detector checkout . Check hardware after insertion

and cabling

• Lasts about 1-2 days (and nights) per side.

• With standalone BPIX software (no XDAQ).

• Access to PP0 required.

• What is beeing checked?

– power the full detector or its parts

– can we talk to slow I2C devices e.g. DELAY25?

– check if the clock present

– are all devices drawing the correct current?

– can we program ROCs/TBMs?

– is the token passage complete?

• Completed for –x side, ongoing today for +x side

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Checkout Procedure (II)• Phase II: extensive detector testing and determining optimal settings

• Access to PP0 not needed anymore.

• Run full pixel test and setup software:

– establish all working parameters (DELAY25, ROCs, FED, AOHs,..)

– do the address level calibration

– pixel alive and S-curves for a limited number of pixels per ROC.

– HV test

• Done with the pixel XDAQ based software.

• Not done yet. Start this week (when fast check finished)

• Time estimate: about 3 weeks if everythings goes smooth

• Cannot participate in global runs before finished

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Recent Pictures from Installation23 / 24. July 2008

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Cassette for transport from PSI to CERNca 100kg, 6.5m long

Half of pixel barrel completely assembled and connected

Supply tube detector supply tube

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Lowering at P5

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Magnet (hidden behind cable trays and patch pannels)

Calos

Si strip tracker

Iron + muon stations

Beam pipe

Hole to insert pixel detector !

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First half of pixel barrel installed

Patch pannel 0

Lower temporary insertion rail

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Transport cassetteTemporary insertion rails

Cables of first half of pixel barrel

Second half of pixel barrel

Beam pipe

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Beam pipe

Carbon fiber platewith insertion rails

Inside of right supply tube

Inside of left supply tube

End flange of barrel pixel detector:

Cooling hosesModule signal cables

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Summary

• Pixel barrel assembly finished

• Went pretty smooth and as expected

• System with detector and supply tubes assembled and fully tested at PSI

• Transported as a whole to CERN

• Installed in CMS last week

• Tests ongoing, everything looks good up to now

• Still much to do before we are ready for data takeing

• Many emotional moments in last weeks, but certainly much more to come...